This invention relates to the processing of minerals such as coal and various ores and especially to the separation of solid material of different densities from the mined material. More particularly the invention relates to a multiple cell jigging apparatus that utilizes a hydrodynamic process to clean or concentrate crushed coal or ore.
Jigging devices are frequently used in the mining industry Basicly, these devices utilize water agitation, flow or other hydrodynamic effect to classify and separate materials of different densities. Typical jigging devices of this type are shown in the following U.S. patents:
______________________________________ U.S. Pat. No. Inventor Date ______________________________________ 1,689,536 Silverston 10/30/28 2,082,467 Prins 6/1/37 2,139,047 Tromp 12/6/38 3,204,764 Prins 9/7/65 ______________________________________
These devices depend in their operation on the difference in specific gravity of coal particles or particles of other mined material and on that of the impurities. Bituminous coal for example has a specific gravity of 1.35 whereas most undersirable impurities have a specific gravity of about 1.55 or higher. Typical of the objectionable impurities that occur in coal are slate, pyrite, clay, rock, crystaline sulphur.
In general terms the crushed coal or ore is delivered to the jig or washer where it is submerged in water to form a slurry. Through various means, water currents are formed including both horizontal currents along the flow path and vertical currents that may be generated in any number of ways. The difference in specific gravity between the desirable material and the heavier impurities is magnified when the crushed material is submerged in water and thus the differential is relatively greater.
In view of the hydrodynamic action created, the lighter particles collect near the top of the flow path and the heavier material sinks to the bottom because it is less mobile and does not flow with the current. As a result the lighter material is discharged with the water flow after heavier material or refuse has sunk to a lower level. A subsequent dewatering process produces a "clean" or concentrated coal or ore.
One of the major problems associated with the utilization of many types of mined coal is the high sulphur content. Sulphur, having a specific gravity very close to that of coal is very difficult to separate out by prior art hydrodynamic processes and accordingly the cleaned coal still may contain an undesirable amount of crystaline sulphur. This material is highly objectionable when the coal is burned and has led to severe restrictions on the utilization of coal as an energy source in spite of its ready availability in many areas.
The method and apparatus of the present invention provide for an improved cleaning and concentration of coal and other ore and not only resolve the difficulties described above but afford other features and advantages heretofore not obtainable.